U.S. patent application number 13/818955 was filed with the patent office on 2014-01-30 for organic radical polyimide electrode active material, and electrochemical device comprising same.
This patent application is currently assigned to KYUNGPOOK NATIONAL UNIVERSITY-ACADEMIC COOPERATION FOUNDATION. The applicant listed for this patent is Hwa Jeong Kim, Young Kyoo Kim, Hye Na Lee. Invention is credited to Hwa Jeong Kim, Young Kyoo Kim, Hye Na Lee.
Application Number | 20140030593 13/818955 |
Document ID | / |
Family ID | 47009862 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140030593 |
Kind Code |
A1 |
Kim; Young Kyoo ; et
al. |
January 30, 2014 |
ORGANIC RADICAL POLYIMIDE ELECTRODE ACTIVE MATERIAL, AND
ELECTROCHEMICAL DEVICE COMPRISING SAME
Abstract
Disclosed herein is an organic radical polyimide, represented by
Formula I below: ##STR00001## The organic radical polyimide can be
applied to a cathode, an anode or the like, and can be widely
applied to an organic solar cell, an organic transistor, organic
memory or the like. Further, the organic radical polyimide can be
used to manufacture a secondary battery having high energy density
because it has high radical density. Further, the organic radical
polyimide can be formed into an ultrathin film such as a polymer
film and can be used to manufacture a flexible next-generation
battery because it does not include metal components and causes a
stable oxidation-reduction reaction.
Inventors: |
Kim; Young Kyoo; (Buk-gu,
KR) ; Lee; Hye Na; (Dalseong-gun, KR) ; Kim;
Hwa Jeong; (Buk-gu, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kim; Young Kyoo
Lee; Hye Na
Kim; Hwa Jeong |
Buk-gu
Dalseong-gun
Buk-gu |
|
KR
KR
KR |
|
|
Assignee: |
KYUNGPOOK NATIONAL
UNIVERSITY-ACADEMIC COOPERATION FOUNDATION
Daegu
KR
|
Family ID: |
47009862 |
Appl. No.: |
13/818955 |
Filed: |
April 13, 2012 |
PCT Filed: |
April 13, 2012 |
PCT NO: |
PCT/KR12/02827 |
371 Date: |
April 1, 2013 |
Current U.S.
Class: |
429/213 ;
526/263 |
Current CPC
Class: |
H01M 10/052 20130101;
H01M 4/137 20130101; C08G 73/1039 20130101; Y02E 60/10 20130101;
C08G 73/10 20130101; H01M 4/608 20130101 |
Class at
Publication: |
429/213 ;
526/263 |
International
Class: |
H01M 4/60 20060101
H01M004/60 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 2011 |
KR |
10-2011-0034830 |
Claims
1. An organic radical polyimide, represented by Formula 1 below:
##STR00023## wherein A is a substituted or unsubstituted aryl group
of 6 to 24 carbon atoms; and B is selected from the group
consisting of a substituted or unsubstituted aryl group of 6 to 24
carbon atoms, a substituted or unsubstituted alkyl group of 1 to 6
carbon atoms and a substituted or unsubstituted alkoxy group of 1
to 6 carbon atoms, and is condensed with an adjacent pyrrolidine
ring to form a ring.
2. The organic radical polyimide of claim 1, wherein A and B are
each independently further substituted with one or more selected
from the group consisting of a hydrogen atom, a heavy hydrogen
atom, a cyano group, a halogen atom, a hydroxy group, a nitro
group, a substituted or unsubstituted alkyl group of 1 to 6 carbon
atoms and a substituted or unsubstituted aryl group of 6 to 24
carbon atoms.
3. The organic radical polyimide of claim 1, wherein the compound
represented by Formula 1 above is any one selected from the group
consisting of compounds represented by Formulae 3 to 9:
##STR00024## ##STR00025##
4. An electrode, comprising the organic radical polyimide of claim
1.
5. The electrode of claim 4, wherein the electrode is a
cathode.
6. An electrochemical device, comprising: a cathode; an anode; and
an electrolyte, wherein the cathode or anode is an electrode
comprising the organic radical polyimide of claim 1.
7. The electrochemical device of claim 6, wherein the
electrochemical device is a lithium secondary battery.
8. An electrode, comprising the organic radical polyimide of claim
2.
9. The electrode of claim 8, wherein the electrode is a
cathode.
10. An electrode, comprising the organic radical polyimide of claim
3.
11. The electrode of claim 10, wherein the electrode is a
cathode.
12. An electrochemical device, comprising: a cathode; an anode; and
an electrolyte, wherein the cathode or anode is an electrode
comprising the organic radical polyimide of claim 2.
13. The electrochemical device of claim 12, wherein the
electrochemical device is a lithium secondary battery.
14. An electrochemical device, comprising: a cathode; an anode; and
an electrolyte, wherein the cathode or anode is an electrode
comprising the organic radical polyimide of claim 3.
15. The electrochemical device of claim 14, wherein the
electrochemical device is a lithium secondary battery.
Description
TECHNICAL FIELD
[0001] The present invention relates to an organic radical
polyimide electrode active material and, more particularly, to an
organic radical polyimide electrode active material which can be
used to realise an electrochemical device having high energy
density because of its high radical density, which can be formed
into an ultrathin film such as a polymer film, and which can be
utilized for a flexible electrochemical device, and to an
electrochemical device including the same.
BACKGROUND ART
[0002] In secondary batteries, an inorganic material, such as
carbon, lithium-cobalt oxide (LiCoO.sub.2) or the like, is used as
an electrode material. Therefore, no matter how such an inorganic
electrode material is made thin, it may be easily cracked and thus
destroyed when it is bent, so there is a problem in that it is
difficult to apply it to next-generation batteries such as flexible
ultrathin batteries and the like.
[0003] In order to overcome the above problem, NEC Corporation has
developed polymers containing an organic radical. However, most of
such polymers have low heat resistance, so there is a problem in
that it is difficult to assure the lifespan of secondary
batteries.
[0004] Recently, a method of stabilizing an organic radical polymer
having a polynorbornene structure by curing polymer chains among
themselves has been reported. However, this method is problematic
in that it is difficult to increase the degree of curing because
reactions occur only when polymer chains are in very close
proximity to one another, and, particularly, in that, when a
conventional inorganic electrode material, such as carbon or the
like, is mixed with this organic radical polymer in order to
increase an electrode capacitance, there is an increased tendency
for polymer chains to keep away from each other.
[0005] Therefore, it is keenly required to develop an organic
radical polymer electrode active material which can overcome the
problem of low density and low conductivity, which does not cause a
problem even when it is mixed with other inorganic electrode
materials and which can be formed into a thermostable and flexible
thin film.
DISCLOSURE
Technical Problem
[0006] Accordingly, the present invention has been devised, to
solve the above-mentioned problems, and a first object, of the
present invention is to provide an organic radical polyimide which
is a novel electrode active material, which has high radical
density and induces a stable oxidation-reduction reaction, and
which can be formed into a flexible polymer film.
[0007] A second object of the present invention is to provide a
flexible electrochemical device which vases an electrode including
the novel organic radical polyimide and which can be made
ultrathin.
[0008] A third second object of the present invention is to provide
an electrochemical device which is a lithium secondary battery.
Technical Solution
[0009] In order to accomplish the first object, an aspect of the
present invention provides an organic radical polyimide which is a
novel electrode active material represented by Formula 1 below:
##STR00002##
[0010] wherein A is a substituted or unsubstituted aryl group of 6
to 24 carbon atoms; and B is selected from the group consisting of
a substituted or unsubstituted aryl group of 6 to 24 carbon atoms,
a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms
and a substituted or unsubstituted alkoxy group of 1 to 6 carbon
atoms, and is condensed with an adjacent pyrrolidine ring to form a
ring.
[0011] In Formula 1 above, A and B may be each independently
further substituted with one or more selected from the group
consisting of a hydrogen atom, a heavy hydrogen atom, a cyano
group, a halogen atom, a hydroxy group, a nitro group, a
substituted or unsubstituted alkyl group of 1 to 6 carbon sterns
and a substituted or unsubstituted aryl group of 6 to 24 carbon
atoms.
[0012] In order to accomplish the second object, another aspect of
the present invention provides an electrode including the organic
radical polyimide represented by Formula 1 above. Here, the
electrode may be a cathode.
[0013] Still another aspect of the present invention provides an
electrochemical device, including: a cathode; an anode; and an
electrolyte, wherein the cathode or anode is an electrode including
the organic radical polyimide represented by Formula 1 above.
[0014] Here, the electrochemical device may be a lithium secondary
battery.
Advantageous Effects
[0015] As described above, the organic radical polyimide according
to the present invention can be applied to a cathode, an anode or
the like, and can be widely applied to an organic solar cell, an
organic transistor, organic memory or the like. Further, the
organic radical polyimide can be used to manufacture a secondary
battery having high energy density because it has high radical
density. Further, the organic radical polyimide can be formed into
an ultrathin film such as a polymer film and can be used to
manufacture a flexible next-generation battery because it does not
include metal components and causes a stable oxidation-reduction
reaction.
DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a graph showing the ESR spectrum of PMDA-TDAQ PI
according to an embodiment of the present invention;
[0017] FIG. 2 is a graph showing the result of TGA analysis of
PMDA-TDAQ PI according to an embodiment of the present
invention;
[0018] FIG. 3 is a graph showing the result of DSC analysis of
PMDA-TDAQ PI according to an embodiment of the present
invention;
[0019] FIG. 4 is a graph showing the result of DSC analysis of
PMDA-TDAQ PI according to an embodiment of the present
invention;
[0020] FIG. 5 is a graph showing the result of MALDI-TOF-MS
analysis of a center block material synthesized in the present
invention;
[0021] FIG. 6 is a graph showing the result of .sup.13C-NMR
analysis of a center block material synthesized in the present
invention;
[0022] FIG. 7 is a graph comparing the absorbance spectrum of a
separated and refined TDAQ product synthesized in the present
invention with the absorbance spectrum of only a center block
material;
[0023] FIG. 8 is a graph comparing the ESR spectrum of only a side
block material synthesized in the present invention with the ESR
spectrum of TDAQ;
[0024] FIGS. 9A to 9C show images evaluating the flexibility
characteristics of PMDA-TDAQ PI according to an embodiment of the
present invention; and
[0025] FIG. 10 is a schematic section view showing the structure of
a lithium secondary battery according to the present invention.
BEST MODE
[0026] Hereinafter, preferred embodiments of the present invention
will be described in detail.
[0027] The present invention provides an organic radical polyimide
which is a novel electrode active material represented by formula 1
below:
##STR00003##
[0028] The present invention relates to the synthesis of a
polyimide containing an organic radical, and, particularly, is
characterized in that a diamine component constituting a polyimide
is bonded with two or more organic radicals.
[0029] Further, in the course of finally synthesizing an organic
radical polyimide, an organic radical polyamic acid represented by
Formula 2 below is synthesized:
##STR00004##
[0030] wherein A is a substituted or unsubstituted aryl group of 6
to 24 carbon atoms; and B is selected from the group consisting of
a substituted or unsubstituted aryl group of 6 to 24 carbon atoms,
a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms
and a substituted or unsubstituted alkoxy group of 1 to 6 carbon
atoms, and is condensed with an adjacent pyrrolidine ring to form a
ring.
[0031] The organic radical polyamic acid can be coated by wet
coating because its solubility in an organic solvent is high, and
it is finally converted into an organic radical polyimide by heat
treatment or the like. The finally-prepared organic radical
polyimide can be dissolved in a solvent depending on the kind of
dianhydride of the components constituting the polyimide.
[0032] Therefore, the present invention is characterized in that
there is no problem even when the organic radical polyimide is
mixed with a conventional inorganic electrode material, such as
carbon or the like, because the heat resistance thereof is
influenced by a polymer intra-chain reaction, not a polymer
inter-chain reaction.
[0033] In particular, in the organic radical polyimide of the
present invention, a high-strength polyimide, which is not
dissolved in a solvent at all, is advantageous in that it can be
formed into a thin film electrode by dissolving a soluble polymer
precursor in various solvents because it is prepared by
thermally-imidizing organic radical polyamic acid which is a
soluble precursor. Further, the high-strength polyimide is
characterized in that processability is very high because it can be
synthesized such that the organic radical polyimide itself becomes
soluble by inserting a soluble group into a polyimide
structure.
[0034] Further, in the case where insoluble polyimide is directly
synthesized without performing a precursor process, when this
insoluble organic radical polyimide powder is mixed with soluble
polyimide (or a precursor thereof), heat resistance can be
improved, and functions can be varied.
[0035] Specific examples of an alkyl group, which is a substituent
group used in the present invention, may include methyl, ethyl,
propyl, iso-butyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl,
and the like. At least one hydrogen atom of the alkyl group may be
substituted with a hydroxy group, a nitro group, a cyano group, a
silyl group (in this case, referred to as "an alkylsilyl group"), a
substituted or unsubstituted amino group (--NH.sub.2, --NH(R),
--N(R')(R''), R' and R'' are each independently an alkyl group of 1
to 10 carbon atoms, and, in this case, referred to as "an
alkylamino group"), a hydrazine group, a hydrazone group, a
carboxylic group, a sulfonic group, a phosphoric group, an alkyl
group, a halogenated alkyl group, an alkenyl group or an aryl
group.
[0036] Specific examples of an alkoxy group, which is a substituent
group used in the present invention, may include methoxy, ethoxy,
propoxy, iso-butyloxy, sec-butyloxy, pentyloxy, iso-amyloxy,
hexyloxy, and the like. At least one hydrogen atom of the alkoxy
group, the same as the alkyl group, may be substituted with a
substituent group.
[0037] The aryl group used in the present invention is an aromatic
system including one or more rings, and the rings may be bonded or
fused with each other by a pendant method. Further, the aryl group
includes a noncondensible aromatic group. Specific examples of the
aryl group may include aromatic groups, such as phenyl, naphthyl,
anthracenyl, phenanthryl, pyrenyl, chrysenyl, fluoranthenyl and the
like, and specific examples of the noncondensible aromatic group
may include biphenyl, terphenyl and the like. At least one hydrogen
atom of the aryl group, the same as the alkyl group, may be
substituted with a substituent group (for example, an aryl group
substituted with an amino group is referred to as "an arylamino
group, and an aryl group substituted with an oxy group is referred
to as "an aryloxy group").
[0038] In the present invention, the term "unsubstituted or
substituted" means that any group is unsubstituted or substituted
with one or more selected from the group consisting of a hydrogen
atom, a heavy hydrogen atom, a cyano group, a halogen atom, a
hydroxy group, a nitro group, a substituted or unsubstituted alkyl
group of 1 to 6 carbon atoms and a substituted or unsubstituted
aryl group of 6 to 24 carbon atoms.
[0039] According to an embodiment of the present invention, the
compound represented by Formula 1 above may be any one selected
from the group consisting of compounds represented by Formulae 3 to
9:
##STR00005## ##STR00006##
[0040] The present invention relates to a lithium secondary battery
including the organic radical polyimide cathode active material as
a constituent. Generally, a lithium secondary battery includes a
cathode, an anode, a separation membrane and a lithium
salt-containing nonaqueous electrolyte.
[0041] FIG. 10 shows an exemplary structure of a lithium secondary
battery according to the present invention.
[0042] Referring to FIG. 10, in a lithium secondary battery, an
anode 11 and a cathode 13 are covered with a battery case in a
state in which a separation membrane is disposed therebetween. The
cathode 11 is provided at the upper end thereof with cathode
terminals for electrically connecting components constituting the
battery with external appliances, and the anode 13 is also provided
at the upper end thereof with anode terminals for electrically
connecting components constituting the battery with external
appliances.
[0043] Hereinafter, a cathode, an anode, a separation membrane, an
electrolyte and the like, which are constituents of a secondary
battery, will be described in more detail.
[0044] The cathode 13 includes the organic radical polyimide of the
present invention. For example, the cathode 13 is prepared by
applying a mixture of the organic radical polyimide of the present
invention, a conducting agent and a binder onto a cathode collector
14 and then drying the mixture. If necessary, a filler may be added
to the mixture.
[0045] Generally the cathode collector is made to a thickness of 3
to 500 .mu.m. Such a cathode collector is not limited as long as it
has high conductivity while not causing a chemical change in the
battery. For example the cathode collector may be made of stainless
steel, aluminum, nickel, titanium, calcined carbon or may be made
of aluminum or stainless steel surface-treated with carbon, nickel,
titanium, silver or the like. The surface of the cathode collector
may be made uneven to increase the adhesivity of the cathode
collector to a cathode active material. The cathode collector may
be fabricated in various forms, such as film, sheet, foil, net,
porous body, foam, nonwoven fabric and the like.
[0046] The conducting agent is added in an amount of 1 to 50 wt %
based on the total amount of the mixture including a cathode active
material. Such a conducting agent is not limited as long as it has
high conductivity while not causing a chemical change in the
battery. Examples of the conducting agent may include: graphite
such as natural graphite, synthetic graphite or the like; carbon
black such as carbon black, acetylene black, Ketjen black, channel
black, furnace black, lamp black, thermal black or the like;
conductive fiber such as carbon fiber, metal fiber or the like;
metal powder such as carbon fluoride powder, aluminum powder,
nickel powder or the like; conductive whiskey such as zinc oxide,
potassium titanate or the like; conductive oxides such as titanium
oxide and the like; and conductive materials such as polyphenylene
derivatives and the like. According to circumstances, the addition
of the conducting agent may be omitted when a cathode active
material is coated with another conductive layer.
[0047] The binder is a component for assisting the bonding between
an active material and a conducting agent and the bonding between
an active material and a collector. Generally, the binder is added
in an amount of 1 to 50 wt % based on the total amount of the
mixture including a cathode active material. Examples of the binder
may include polyvinylidene fluoride, polyvinyl alcohol,
carboxymethylcellulose (CMC), starch, hydroxypropylcellulose,
recycled cellulose, polyvinylpyrrolidone, tetrafluoroethylene,
polyethylene, polypropylene, ethylene-propylene-diene terpolymer
(EPDM), sulfonated EPDM, styrene-butylene rubber, fluorine rubber,
various polymers, and the like.
[0048] The filler is a component for controlling the expansion of a
cathode, and is selectively used. The filler is not limited as long
as it is a fibrous material while not causing a chemical change in
the battery. Examples of the filer may include: olefin polymers
such as polyethylene, polypropylene and the like; and fibrous
materials such as glass fiber, carbon fiber and the like.
[0049] The anode 11 is prepared by applying an anode material onto
an anode collector and then drying the anode material. If
necessary, the above-mentioned components may be added thereto.
[0050] Generally, the anode collector is made to a thickness of 3
to 500 .mu.m. Such an anode collector is not limited as long as it
has high conductivity while not causing a chemical change in the
battery. For example, the anode collector may be made of copper,
stainless steel, aluminum, nickel, titanium, calcined carbon, may
be made of copper or stainless steel surface-treated with carbon,
nickel, titanium, silver or the like or may be made of an
aluminum-cadmium alloy. Further, the surface of the anode
collector, the same as the cathode collector may be made uneven to
increase the adhesivity of the anode collector to an anode active
material. The anode collector may be used in various forms, such as
film, sheet, foil, net, porous boy, foam, nonwoven fabric and the
like.
[0051] Example of the anode material may include: carbon such as
hard carbon, graphite carbon or the like; metal composite oxides
such as Li.sub.xFe.sub.2O.sub.3 (0.ltoreq.x.ltoreq.1),
Li.sub.xWO.sub.2 (0.ltoreq.x.ltoreq.1),
Sn.sub.xMe.sub.1-xMe'.sub.yO.sub.z (Me: Mn, Fe, Fb, Ge; Me': Al, B,
P, Si, group I elements, group II elements, group III elements in
the periodic table, halogen; 0<x.ltoreq.1; 1.ltoreq.y.ltoreq.3;
1.ltoreq.z.ltoreq.8); lithium metal; lithium alloys; silicon
alloys; tin alloys; oxides such as SnO, SnO.sub.2, PbO, PbO.sub.2,
Pb.sub.2O.sub.3, Pb.sub.3O.sub.4, Sb.sub.2O.sub.3, Sb.sub.2O.sub.4,
Sb.sub.2O.sub.5, GeO, GeO.sub.2, Bi.sub.2O.sub.3, Bi.sub.2O.sub.4,
Bi.sub.2O.sub.5 and the like; conductive polymers such as
polyacetylene and the like; and Li--Co--Ni-based materials.
[0052] The separation membrane is disposed between the anode and
the cathode. An insulating thin film having high ionic permeability
and high mechanical strength is used as the separation
membrane.
[0053] Generally, the separation membrane has a pore diameter of
0.01.about.10 .mu.m and a thickness of 5.about.300 .mu.m. As the
separation membrane, a sheet or nonwoven fabric made of am olefin
polymer such as polypropylene having chemical resistance and
hydrophobicity, glass fiber or polyethylene is used. When a solid
electrolyte, such as a solid polymer or the like, is used as an
electrolyte, the solid electrolyte may serve both as a separation
membrane and an electrolyte.
[0054] The lithium salt-containing nonaqueous electrolyte includes
a nonaqueous electrolyte and lithium. As the nonaqueous
electrolyte, a liquid electrolyte, a solid electrolyte, an
inorganic solid electrolyte or the like may be used.
[0055] As the nonaqueous liquid electrolyte, a nonprotonic organic
solvent, such as N-methyl-2-pyrrolidinone, propylene carbonate,
ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl
carbonate, gamma-butyrolactone, 1,2-dimethoxyethane,
tetrahydroxyfuran, 2-methyl tetrahydrofuran, dimthylsulfoxide,
1,3-dioxolan, formamide, dimethylformamide, dioxolan, acetonitrile,
nitromethane, methyl formate, methyl acetate, trimester phosphate,
trimethoxy methane, a dioxolan derivative, sulfolane, methyl
sulfolane, 1,3-dimethyl-2-imidazolidinone, a propylene carbonate
derivative, a tetrahydrofuran derivative, ether, methyl propionate,
ethyl propionate or the like, may be used.
[0056] As the organic solid electrolyte, a polyethylene derivative,
a polyethylene oxide derivative, a polypropylene oxide derivative,
a phosphoric ester polymer, poly agitation lysine, polyester
sulfide, polyvinyl alcohol, polyvinylidene fluoride, a polymer
having an ionic dissociation group or the like may be used.
[0057] As the inorganic solid electrolyte, nitride, halogenide or
sulfate of lithium (Li), such as Li.sub.3N, LiI, Li.sub.5NI.sub.2,
Li.sub.3N--LiI--LiOH, LiSiO.sub.4, LiSiO.sub.4--LiI--LiOH,
Li.sub.2SiS.sub.3, Li.sub.4SiO.sub.4, Li.sub.4SiO.sub.4--LiI--LiOH,
Li.sub.3P.sub.4--Li.sub.2S--SiS.sub.2 or the like, may be used.
[0058] The lithium salt is a material which is easily dissolved in
the nonaqueous electrolyte. Examples of the lithium salt may
include LiCl, LiBr, LiI, LiClO.sub.4, LiBF.sub.4,
LiF.sub.10Cl.sub.10, LiPF.sub.6, LiCF.sub.3SO.sub.3,
LiCF.sub.3CO.sub.2, LiAsF.sub.6, LiSbF.sub.6, LiAlCl.sub.4,
CH.sub.3SO.sub.3Li, CF.sub.3SO.sub.3Li,
(CF.sub.3SO.sub.2).sub.2NLi, chloroboran lithium, lower aliphatic
lithium carboxylate, lithium phenylborate, imide and the like.
[0059] Further, in order to improve the charge-discharge
characteristics, flame retardancy and the like of the battery,
pyridine, triethylphosphite, triethanolamine, cyclic ether,
ethylenediamine, n-glyme, hexatriamide phosphate, nitrobenzene
derivative, sulfur, quinine-imine dye, N-oxazolidinone,
N,N-imidazolidine, ethyleneglycol dialkyl ether, ammonium salt,
pyrrole, 2-methoxy ethanol, aluminum trichloride or the like may be
added to the nonaqueous electrolyte. According to circumstances,
the nonaqueous electrolyte may further include a solvent containing
halogen such as carbon tetrachloride, ethylene trifluoride or the
like in order to provide flame resistance, and may further include
carbon dioxide gas in order to improve high-temperature storage
characteristics.
MODE FOR INVENTION
[0060] Hereinafter, the present invention will be described in more
detail with reference to the following Examples. However, these
Examples are set forth to illustrate the present invention, and it
will obvious to those skilled in the art that the scope of the
present invention is not limited thereto.
EXAMPLES
Preparation Example 1
Synthesis of Center Block Material
##STR00007##
[0062] In order to substitute oxygen (O) of diaminoanthraquinone
(DAQ) with sulfur (S), DAQ and Lawesson's reagent were put into a
flask, and then a reaction was conducted at 110.degree. C. for 24
hours to obtain a first reaction product. Subsequently, an aromatic
mixed solvent, a catalyst and the first reaction product were put
into a three-neck flask, and then a reaction started at 100.degree.
C. At an early stage of the reaction, the reaction mixture was red
and opaque, but became dark with the passage of time. After several
hours had passed since the reaction, the reaction mixture changed
into a clear brown reaction product solution. After the reaction
had finished, the reaction product solution became very dark and
was partially precipitated as soon as the temperature decreased to
room temperature. After the reaction was finished, the reaction
product solution stabilised at room temperature was shifted to
another flask, and was then separated and purified. Subsequently,
the purified reaction product solution was repetitively
recrystallized to obtain a precipitate. This precipitate was
centrifugally separated and then dried in a vacuum to finally
obtain a center block material. The finally-obtained center block
material was a very dark brown solid material.
[0063] The synthesized center block material was basically analyzed
using MALDI-TOF-MS and .sup.13C-NMR, and the results thereof are
shown in FIGS. 5 and 6.
Preparation Example 2
Synthesis of TDAQ
##STR00008##
[0065] The obtained S-substituted DAQ was reacted with 4-Oxo-TEMPO
and a catalyst (P(OEt).sub.3) at 110.degree. C. for 24 hours to
obtain TDAQ. First, center block and side block were dissolved in
DMSO to prepare a solution, a catalyst was added to the solution,
and then the solution was stirred to be uniformly dispersed. The
uniformly-dispersed solution was heated to 120.degree. C. and then
reacted for about 24 hours. At the end of the reaction, the color
of the solution had become dark compared to the color thereof at an
early stage of the reaction. Therefore, it was ascertained that the
center block had bonded with a side block.
[0066] The reaction product solution including the bonded center
block and side block was separated and purified using column
chromatography. The purified reaction product solution was slowly
heated, and simultaneously evaporated using a rotary evaporator to
remove a solvent therefrom, thus obtaining a solid reaction
product. Subsequently, the solid reaction product was
recrystallized by repetitively using a solvent and a non-solvent to
remove unreacted materials therefrom. Finally, the recrystallized
solid reaction product was centrifugally separated to obtain a
primarily-purified solid reaction product.
[0067] The obtained primarily-purified solid reaction product was
analyzed by a general analysis method, and thus it was ascertained
that TDAQ was synthesized. FIG. 7 is a graph comparing the
absorbance spectrum of the separated and refined TDAQ product with
the absorbance spectrum of only center block. In FIG. 7, it can be
seen from the structure of TDAQ that band edge was shifted toward
long wavelength by about 100 nm.
[0068] In order to confirm the existence of the synthesized TDAQ
product, an electron spin resonance (ESR) spectrum was measured.
First, the ESR spectrum of side block was measured, and ESR signals
were accurately measured at a magnetic field of 320.about.330 ml.
Therefore, it can be confirmed that radicals exist in the TEMPO
derivative of the side block. Further, as the result of measuring
the ESR spectrum of TDAQ, ESR signals were measured at a magnetic
field of 320.about.330 mT, and thus it can be ascertained that the
ESR spectrum of TDAQ is very similar to the ESR spectrum of the
side block.
[0069] However, it was predicted that the difference between the
side block and TDAQ would exist because they are different from
each other in molecular structure and environment, so the two ESR
spectrums were compared with each other. As shown in FIG. 8, it can
be seen that two ESR peaks are very similar to each other at a
magnetic field of 320.about.330 mT, but left signal peaks thereof
are different from each other. That is, it can be seen that the
left peak of TDAQ leans toward a higher magnetic field. Therefore,
it can be ascertained that the center block is bonded with two side
blocks to have a symmetric structure, and thus the signal of TEMPO
radical moves in a direction toward a high magnetic field.
Preparation Example 3
Synthesis of PMDA-TDAQ Polyamic Acid
##STR00009##
[0071] PMDA-TDAQ PAA, which is a solvent-soluble polyamic acid, was
synthesized by reacting TDAQ and PMDA at low temperature (0.degree.
C.) for 72 hours without using a catalyst. After the reaction was
finished, a solution was precipitated by non-solvent to obtain
solid matter, and then the solid matter was dried. Specifically,
first, TDAQ was put into a three-neck flask, and was then
completely dissolved in a mixed solvent to prepare a mixed
solution. Subsequently, a soluble comonomer and a catalyst were
added to the mixed solution, and then the mixed solution was
stirred until it became uniform. Then, the uniformly stirred mixed
solution was reacted for about 72 hours while the temperature was
controlled. The color of the mixed solution at an early stage of
the reaction was clear light brown, but gradually changed to dark
brown with the passage of time, and this color was maintained until
the reaction was finished. After the reaction had finished, the
mixed solution was precipitated by non-solvent and redissolved in a
solvent to separate a catalyst and unreacted substances therefrom.
Subsequently, in order to separate a larger amount of
low-molecular-weight oligomers, the mixed solution was additionally
separated by centrifugal separation or the like to obtain a viscous
liquid polymer. This viscous liquid polymer was solidified to
obtain a solid polymer.
[0072] In order to indirectly evaluate whether PMDA-TDAQ PAA was
properly formed into a polymer, a film forming test was conducted.
The formation of a film was observed by drop-casting the obtained
PMDA-TDAQ PAA solution onto a slide glass and then soft-baking the
drop-cast PMDA-TDAQ PAA solution. In this case, it was ascertained
that the light-colored PMDA-TDAQ PAA solution was formed into a
film after soft-baking. Therefore, it was ascertained that the
synthesized PMDA-TDAQ PAA is a polymer having a high molecular
weight sufficient for forming a film.
Preparation Example 4
Synthesis of BTDA-TDAQ Polyamic Acid
##STR00010##
[0074] BTDA-TDAQ PAA, which is a solvent-soluble polyamic acid, was
synthesized by reacting TDAQ and BTDA at low temperature (0.degree.
C.) for 72 hours without using a catalyst. After the reaction had
finished, a solution was precipitated by non-solvent to obtain
solid matter, and then the solid matter was dried. The color of the
solution at an early stage of the reaction was already red because
of inherent characteristics of BTDA. After the reaction had
finished, a polymer was precipitated (recrystallized) by using a
solvent/non-solvent system to obtain a solid polymer.
[0075] In order to indirectly evaluate the molecular weight of the
separated BTDA-TDAQ PAA, a film forming test was conducted using a
drop casting method. As a result, it can be ascertained that a
film, not particles, is formed after soft-baking a polymer
solution. However, it can be ascertained that the film partially
includes particles. Therefore, the polymer solution was
repetitively separated and purified to remove particles therefrom,
and was then formed into a film. As the result of observing the
process of forming this film, it can be seen that a clean film can
be obtained by only a dilute solution.
Preparation Example 5
Synthesis of BTDA-TDAQ Polyimide
##STR00011##
[0077] BTDA-TDAQ PI was synthesized by reacting TDAQ and BTDA with
triethylamine (TEA) as a catalyst at 160 for 72 hours. At an early
stage of the reaction, the reaction product solution was
transparent and red, but the color thereof was somewhat changed
with the passage of time. After the reaction had finished, the
reaction product solution became dark red when the temperature
decreased to room temperature.
[0078] After the reaction was finished, the reaction product
solution was recrystallized by properly using a solvent/non-solvent
system and centrifugally-separated to selectively obtain a
high-molecular-weight polymer. The obtained high-molecular-weight
polymer was dried in a vacuum to obtain a solid polymer. As the
result of conducting a basic film forming test, it can be
ascertained that a film is formed.
Preparation Example 6
Synthesis of PMDA-TDAQ Polyimide
##STR00012##
[0080] PMDA-TDAQ PI was synthesized in the same manner as in
Preparation Example 5, except that TDAQ and PMDA were reacted with
triethylamine (TEA) as at catalyst at 160.degree. C. for 72
hours.
Preparation Example 7
Synthesis of BCDA-TDAQ Polyamic Acid
##STR00013##
[0082] BCDA-TDAQ PAA, which is a solvent-soluble polyamic acid, was
synthesized in the same manner as in Preparation Example 4, except
that TDAQ and BCDA were reacted at low temperature (0.degree. C.)
for 72 hours without using a catalyst. After the reaction had
finished, a solution was precipitated by non-solvent to obtain
solid matter, and then the solid matter was dried.
Preparation Example 8
Synthesis of BCDA-TDAQ Polyimide
##STR00014##
[0084] BCDA-TDAQ PI was synthesized in the same manner as in
Preparation Example 5, except that TDAQ and BCDA were reacted with
triethylamine (TEA) as a catalyst at 160.degree. C. for 72
hours.
Preparation Example 9
Synthesis of NTCDA-TDAQ Polyamic Acid
##STR00015##
[0086] NTCDA-TDAQ PAA, which is a solvent-soluble polyamic acid,
was synthesized in the same manner as in Preparation Example 4,
except that TDAQ and NTCDA were reacted at low temperature
(0.degree. C.) for 72 hours without using a catalyst. After the
reaction had finished, a solution was precipitated by non-solvent
to obtain solid matter, and then the solid matter was dried.
Preparation Example 10
Synthesis of NTCDA-TDAQ Polyimide
##STR00016##
[0088] NTCDA-TDAQ PI was synthesized in the same manner as in
Preparation Example 5, except that TDAQ and NTCDA were reacted with
triethylamine (TEA) as a catalyst, at 160.degree. C. for 72
hours.
Preparation Example 11
Synthesis of PTCDA-TDAQ Polyamic Acid
##STR00017##
[0090] PTCDA-TDAQ PAA, which is a solvent-soluble polyamic acid,
was synthesized in the same manner as in Preparation Example 4,
except that TDAQ and PTCDA were reacted at low temperature
(0.degree. C.) for 72 hours without using a catalyst. After the
reaction had finished, a solution was precipitated by non-solvent
to obtain solid matter, and then the solid matter was dried.
Preparation Example 12
Synthesis of PTCDA-TDAQ Polyimide
##STR00018##
[0092] PTCDA-TDAQ PI was synthesized in the same manner as in
Preparation Example 5, except that TDAQ and PTCDA were reacted with
triethylamine (TEA) as a catalyst at 160.degree. C. for 72
hours.
Preparation Example 13
Synthesis of BPDA-TDAQ Polyamic Acid
##STR00019##
[0094] BPDA-TDAQ PAA, which is a solvent-soluble polyamic acid, was
synthesized in the same manner as in Preparation Example 4, except
that TDAQ and BPDA were reacted at low temperature (0.degree. C.)
for 72 hours without using a catalyst. After the reaction had
finished, a solution was precipitated by non-solvent to obtain
solid matter, and then the solid matter was dried.
Preparation Example 14
Synthesis of BPDA-TDAQ Polyimide
##STR00020##
[0096] BPDA-TDAQ PI was synthesized in the same manner as in
Preparation Example 5, except that TDAQ and BPDA were reacted with
triethylamine (TEA) as a catalyst at 160.degree. C. for 72
hours.
Preparation Example 15
Synthesis of 6FDA-TDAQ Polyamic Acid
##STR00021##
[0098] 6FDA-TDAQ PAA, which is a solvent-soluble polyamic acid, was
synthesized in the same manner as in Preparation Example 4, except
that TDAQ and 6FDA were reacted at low temperature (0.degree. C.)
for 72 hours without using a catalyst. After the reaction had
finished, a solution was precipitated by non-solvent to obtain
solid matter, and then the solid matter was dried.
Preparation Example 16
Synthesis of BPDA-TDAQ Polyimide
##STR00022##
[0100] 6FDA-TDAQ PI was synthesized in the same manner as in
Preparation Example 5, except that TDAQ and 6FDA were reacted with
triethylamine (TEA) as a catalyst at 160.degree. C. for 72
hours.
Evaluation Example 1
Evaluation of PMDA-TDAQ PI According to the Present Invention
[0101] (1) As shown in FIG. 1, from the result of the ESR spectrum
of PMDA-TDAQ PI, it can be ascertained that, during a synthesis
process, a radical is maintained without being decomposed.
[0102] (2) As shown in FIG. 2, from the result of TGA analysis of
PMDA-TDAQ PI, it can be ascertained that the initial decomposition
temperature thereof by oxygen is 170.degree. C. or more, and thus a
process of manufacturing an electrode can be carried out in the
air.
[0103] (3) As shown in FIG. 3, from the result of DSC analysis of
PMDA-TDAQ PI, it can be ascertained that two glass transition
temperatures were identified.
[0104] (4) As shown in FIG. 4, from the result of DSC analysis of
PMDA-TDAQ PI, it can be ascertained that the initial glass
transition temperature thereof is 160.degree. C. or more.
Evaluation Example 2
Evaluation of Flexibility Characteristics of Organic Radical
Polyimide According to the Present Invention
[0105] (1) The PMDA-TDAQ PAA precursor polymer synthesized
according to the present invention was applied onto a glass
substrate, and was then thermally-imidized to form a PMDA-TDAQ PI
film.
[0106] (2) The PMDA-TDAQ PI film formed in this way was detached
from the glass substrate, and then the flexibility thereof was
evaluated. The results thereof are shown in FIGS. 9A to 9C.
[0107] (3) From the results, it can be ascertained that a
conventional inorganic electrode for a secondary battery is cracked
or destroyed when it is bent at an angle of 90.degree. to
180.degree., whereas the organic radical polyimide film of the
present invention returns to the original state even alter it is
bent.
[0108] (4) FIG. 9A shows a PI film detached from a substrate, FIG.
9B shows the results of testing the flexibility of the PI film, and
FIG. 9C shows the flexibility of the PI film bent at an angle of
180.degree..
Example 1
Manufacture of a Lithium-Ion Secondary Battery
[0109] The synthesized PMDA-TDAQ PAA precursor polymer was applied
onto an ITO substrate to a thickness of 10 to 1000 nm, and was then
thermally-imidized at a temperature of 150 to 200.degree. C. to
form a PMDA-TDAQ PI cathode.
[0110] The PMDA-TDAQ PI cathode formed in this way was combined
with an anode, and an electrolyte including LiPF.sub.6 and
propylene carbonate was injected, thus manufacturing an organic
radical battery.
[0111] The voltage of the manufactured battery was 3.about.3.3 V,
and the capacitance thereof was approximately 9.0 mAh/g.
Example 2
Manufacture of a Lithium-Ion Secondary Battery
[0112] The synthesized PMDA-TDAQ PAA precursor polymer was applied
onto an ITO substrate to a thickness of 10 to 1000 nm, and was then
thermally-imidized at a temperature of 150 to 200.degree. C. to
form a PMDA-TDAQ PI cathode.
[0113] The PMDA-TDAQ PI cathode formed in this way was coated
thereon with a polymer-gel electrolyte obtained by mixing
polyethylene oxide (PEO) and PVDF-HFP with LiPF.sub.6 and propylene
carbonate to a thickness of 500.about.10000 nm, and was then
combined with a metal electrode (lithium or aluminum), thus
manufacturing an organic radical battery.
[0114] The voltage of the manufactured battery was 2.7.about.3.4 V,
and the capacitance thereof was approximately 60.about.110
mAh/g.
REFERENCE NUMERALS
[0115] 11: anode
[0116] 12: electrolyte
[0117] 13: organic radical polyimide cathode
[0118] 14: collector
[0119] 15: substrate
* * * * *